SCANNING TUNNELING MICROSCOPY DEVELOPMENT FOR IN SITU CORROSION RESEARCH

SCANNING TUNNELING MICROSCOPY HAS DEMONSTRATED THE ABILITY TO IMAGE SURFACES IN A VACUUM, AIR, AND SOLUTION AT THE ATOMIC LEVEL. THE TECHNIQUE HAS ALSO BEEN APPLIED TO POLY- CRYSTALLINE MATERIALS, THE REGIONS NEAR GRAIN BOUNDARIES, ATOMIC DEFECTS, AND THEIR RESPECTIVE LOCALIZED, SPECTROSCOP-IES. THE LOCALIZED CORROSION OF ALUMINUM ALLOYS IN SEA WATER IS A WELL-STUDIED BUT STILL NOT UNDERSTOOD PROBLEM. THE LOCALIZED CORROSION OF ALUMINUM METAL MATRIX COMPOSITES (MMC) HAS BEEN STUDIED AND HAS SHOWN THAT THESE MATERIALS ARE SUSCEPTIBLE TO PITTING THIS PROPOSED RESEARCH WILL BE AN ATTEMPT TO STUDY THE PITTING OF ALUMINUM MMC'S AT THE ATOMIC LEVEL WITH SCANNING TUNNELING MICROSCOPY. THE INITIAL PHASE II EFFORT WILL BE TO BUILD AND TEST THE STM DESIGNED IN PHASE I. THEN THE SYSTEM WILL BE USED UNDERCONTROLLED ELECTROCHEMICAL CONDITIONS TO IMAGE A VARIETY OF ELECTRODES INCLUDING ALUMINUM, IRON-BASED, AND COMPOSITE MATERIALS.